This application is based on Japanese Patent Application No. 2006-71112 filed on Mar. 15, 2006, in Japanese Patent Office, the entire content of which is hereby incorporated by reference.
1. Technical Field
The present invention relates to a recording apparatus and a recording method for performing recording on a recording region of a transported recording material with reference to a detected leading edge of the recording material. More particularly, the invention relates to a recording apparatus and a recording method for performing recording with reference to a leading edge detected in accordance with a margin provided on the recording material.
2. Related Art
In a recording apparatus that records images and characters on a recording material such as paper, a leading edge of a recording sheet supplied from a sheet supply is detected, and recording is performed on a recording region that has a predetermined positional relationship with the leading edge. An optical sensor is known as means for detecting the leading edge of the recording sheet. The optical sensor includes a light-emitting element for emitting light to the recording sheet and a light-receiving element for receiving reflected light. JP-A-2004-90316 discloses an ink jet recording apparatus in which a recording head and an optical sensor are mounted on a carriage.
In this ink jet recording apparatus, images and so on are recorded by ejecting ink droplets from the recording head onto a surface of a recording sheet while repeating an operation of reciprocating the carriage in a main scanning direction of the recording sheet and an operation of transporting the recording sheet in a sub-scanning direction by a predetermined feeding amount. For printing, in a state in which the carriage stands by at a position through which the leading edge of the transported recording sheet passes, the leading edge crossing a detection range of the optical sensor is detected while transporting the recording sheet. Then, ink droplets are ejected from the recording head onto a recording region that has a predetermined positional relationship with the detected leading edge.
In these operations, it is preferable that the optical sensor detect the leading edge of the recording sheet at a position where the leading edge reliably passes, regardless of the size of the recording sheet. For that purpose, a guide mechanism that allows the recording sheet to be transported along one side of a feeding path is provided in some recording apparatuses. In these recording apparatuses, the leading edge of the recording sheet is detected on one side, generally, on the left side, as viewed from the upstream side in the sub-scanning direction.
Unfortunately, the above-described related art has the following problems. During transportation, the recording sheet is sometimes skewed in the sub-scanning direction, for example, because of friction in the feeding path. When skewing occurs, a margin provided around a recording region does not have a uniform width. Alternatively, although recording should be performed so as not to form a margin, a margin is formed outside a range in which ink is ejected from the recording head.
Further, the direction in which skewing occurs is not fixed, and the recording sheet can be skewed to both the right and left in the sub-scanning direction. In this case, when the left leading edge of the recording sheet is detected, as described above, the size of the margin seriously changes in accordance with the direction of skewing.